A cathode-ray tube (CRT) monitor is the type that has been around for years and is large and boxy.
CRT monitors are heavy and they take up a lot of desk space. They have largely been replaced by flat-screen monitors. However some are still used in the design industry since the colour accuracy and brightness of CRT monitors is excellent, and designers need to see true-to-life colours.
Also, CRT monitors are generally cheaper than flat-screen monitors.
Flat-Screen Monitor (TFT or LCD)
Flat-screen monitors are light in weight and they take up very little desk space.
Modern flat-screen monitors have a picture quality that is as good as CRT monitors.
Digital / Multimedia Projector
The image is produced inside the device and then projected out through a large lens, using a powerful light source.
Loudspeakers are essential for applications such as music editing, video conferencing, watching movies, etc.